1. Field of the Invention
The present invention relates to a pressure plate assembly for a multi-disk clutch having a housing arrangement, a pressure plate mounted in the housing arrangement so that the pressure plate is axially movable with respect to the housing arrangement and fixed with respect to rotation relative to the housing arrangement, an intermediate plate mounted in the housing arrangement so that the intermediate plate is axially movable with respect to the housing arrangement and fixed with respect to rotation relative to the housing arrangement, and a release distance preset arrangement for the intermediate plate having at least one sensing element on the intermediate plate. The sensing element rests on an assembly which shifts position during the performance of a releasing movement of the pressure plate and allows the intermediate plate to execute a releasing movement corresponding to the shift of this assembly. The sensing element in contact with the assembly is pretensioned by an intermediate plate releasing force-generating arrangement which acts on the intermediate plate.
2. Description of the Related Art
A dual-disk clutch and a pressure plate assembly for such a clutch are known from German reference DE 37 07 918 C2. This dual-disk clutch includes a pressure plate and an intermediate plate which are installed in a housing and are movable in the same direction as an axis of rotation within a certain limited range with respect to the housing to execute clutch-releasing or clutch-engaging movements. Both the pressure plate and the intermediate plate are connected to the housing by so-called tangential leaf springs or groups of tangential leaf springs. At one end, the tangential leaf springs or groups of tangential leaf springs are attached to the housing. At the other end, these tangential leaf springs or groups of tangential leaf springs are attached to the pressure plate or to the intermediate plate. In these end areas, therefore, the tangential leaf springs are supported on the housing on the one side and on the pressure plate or intermediate plate on the other and thus generate the releasing force required for the execution of the clutch-release operations.
A sensing element is provided on the intermediate plate to detect a position of a group of tangential leaf springs connecting the pressure plate to the housing. More specifically, this sensing occurs in the central part of the circumferential dimension of the tangential leaf springs. The reason for this is that the central area of this group of tangential leaf springs executes a stroke which corresponds approximately to half of the stroke of the pressure plate during the execution of a releasing movement. This stroke of the central area of the tangential leaf springs equal to half the stroke of the pressure plate is then the stroke which the intermediate plate executes in response to a release movement. The sensing of this group of tangential leaf springs does not necessarily have to involve direct physical contact between the sensing element and these tangential leaf springs.
A contact element may be connected to the two support or end areas of the group of tangential leaf springs. The central area of this contact element can thus execute essentially the same stroke as that of the associated central area of the tangential leaf springs.
The pretension of the tangential leaf springs which connect the intermediate plate to the housing ensures that the intermediate plate copies the disengaging or release movement of the pressure plate in a defined manner by traveling a corresponding but reduced releasing distance. Upon the execution of a clutch-engaging operation, a stored-energy device such as, for example, a diaphragm spring then works against the tangential leaf springs of the pressure plate and the tangential leaf springs of the intermediate plate. Here, too, a corresponding reduction occurs with respect to the distance traveled between the pressure plate and the intermediate plate.
In this known pressure plate assembly or dual-disk clutch in which measures are taken to provide for a defined release movement of the intermediate plate upon execution of a clutch-release operation, there is the problem that the intermediate plate in particular may be induced to vibrate in the axial direction when it is not clamped between the two clutch disks. These axial vibrations may be transmitted to other components such as the pressure plate by the sensing element.
It is an object of the present invention to provide a pressure plate assembly for a multi-disk friction clutch which at least reduces the danger of the excitation of vibrations in the area of the intermediate plate without affecting the defined release behavior.
According to the present invention, the object is acheived by a pressure plate assembly for a multi-disk clutch having a housing arrangement, a pressure plate mounted in the housing arrangement so that the pressure plate is axially movable with respect to the housing arrangement and fixed with respect to rotation relative to the housing arrangement, an intermediate plate mounted in the housing arrangement so that the intermediate plate is axially movable with respect to the housing arrangement and fixed with respect to rotation relative to the housing arrangement, a release distance preset arrangement for the intermediate plate having at least one sensing element on the intermediate plate, wherein the sensing element rests on an assembly which shifts position during the performance of a releasing movement of the pressure plate and allows the intermediate plate to execute a releasing movement corresponding to the shift of this assembly, where the sensing element in contact with the assembly is pretensioned by an intermediate plate releasing force-generating arrangement which acts on the intermediate plate.
According to the present invention, at least one rotational coupling projection is further provided on one of the intermediate plate and the housing arrangement which fits into a rotational coupling recess in the other one of the intermediate plate and the housing arrangement, to produce a rotational coupling between the intermediate plate and housing arrangement.
In contrast to the approach known from the state of the art, the pressure plate assembly according to the present invention separates the function of producing the releasing force for the intermediate plate and the function of producing a rotational coupling of the intermediate plate to the housing arrangement. In particular, at least one rotational coupling projection is provided to produce the rotational coupling which fits into an appropriate recess and thus rests against it. The cooperation between the rotational coupling projection and the respective rotational coupling recess provides a very stable rotational coupling between the intermediate plate and the housing arrangement. The rotational coupling projection and the respective rotational coupling recess also ensure that the intermediate plate enters into frictional interaction with the housing arrangement upon execution of axial movements. The frictional interaction counteracts the buildup of vibrations in the area of the intermediate plate. The pressure plate assembly according to the present invention avoids the suspension of the intermediate plate according to the state of the art by means of tangential leaf springs, which is essentially free in the axial direction.
At least one contact surface extending essentially in the same direction as the axis of rotation may be provided on the rotational coupling recess, along which surface the minimum of one rotational coupling projection is able to shift upon execution of a releasing movement of the intermediate plate.
For technical reasons associated with production, it is preferable for the minimum of one rotational coupling projection to be located on the intermediate plate.
The intermediate plate releasing force-generating arrangement may comprise at least one leaf spring element extending approximately in the circumferential direction to provide the releasing force or pretensioning force for the intermediate plate which provides a simple design that is reliable in operation. To generate the pretensioning force, the at least one leaf spring element has a first support area by which it is supported relative to the housing arrangement along the direction of the axis of rotation of the pressure plate assembly and a second support area by which it is supported with respect to the intermediate plate along the direction of the axis of rotation. Accordingly, the releasing force may be generated by at least one leaf spring element as disclosed in the prior art. The freedom of the at least one leaf spring to move in the circumferential direction with respect to the intermediate plate and/or with respect to the housing arrangement according to the present invention makes it impossible for any torque to be transmitted via the at least one leaf spring element. That is, at least one of the support areas of the at least one leaf spring element is able to move essentially in the circumferential direction with respect to the one of the intermediate plate or the housing arrangement on which it is supported. The first support area of the at least one leaf spring element is preferably attached to the housing arrangement such as, for example, by riveting. The intermediate plate releasing force-generating arrangement may also comprise at least one group of leaf spring elements.
According to another embodiment of the present invention, a pressure plate releasing force-generating arrangement may include at least one leaf spring element with a first support area supported relative to the housing arrangement along the direction of the axis of rotation and with a second support area supported relative to the pressure plate along the direction of the axis of rotation.
A defined release distance for the intermediate plate may be provided, for example, in that the at least one sensing element is supported approximately in a central area between the first support area and the second support area of the minimum of one leaf spring element of the pressure plate releasing force-generating arrangement or of the contact element connected thereto for movement in common.
The present invention also relates to a multi-disk friction clutch equipped with the pressure plate assembly according to the present invention.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.